How to assign a type to a cloned object whose values ​​have been changed recursively?

Question

typescript

Hello. I make a deep copy of 1 object into a new object, changing the key values ​​from numbers to strings. How to set the type for a new object, correcting all values ​​to type "string" recursively in depth? Here is the file https://codesandbox.io/s/epic-platform-mezbe

Answer 1

You can add this type:

type RulersMap<R extends Record<string, unknown>> = {
  [K in keyof R]: R[K] extends number
    ? `${R[K]}px`
    : R[K] extends Record<string, unknown>
      ? RulersMap<R[K]>
      : R[K];
};

and cast the result to the type RulersMap<typeof rulers>
The problem is that map-obj types are not very well written for the deep version, although you can write your own if you wish.